Technical Field
Embodiments of the subject matter disclosed herein generally relate to an apparatus and method for safely anchoring a down-hole tool inside a well or casing.
Discussion of the Background
A down-hole tool may be a device used to conduct seismic surveys in down-hole environments, such as, for example, inside of wells used for oil and gas extraction. Down-hole tools may contain seismic sensors, for example, geophones, or other type of sensors, for example, a temperature measuring device. In order to function properly, a down-hole tool that has been lowered into a well may need to be anchored in place with the tool pressed up against the wall of the well or casing. Several tools may be connected together, top to bottom, along with other survey equipment, using a cable, and lowered into the well and/or casing.
FIG. 1 depicts an exemplary down-hole tool and FIG. 2 depicts an exemplary diagram of a down-hole tool. Tool 100 may include a main housing 102, upper cable head 104, lower cable head 106, and anchoring arm 108. A logging cable 110 may be connected to the upper cable head 104 at the top and the lower cable head 106 at the bottom of the seismic tool 100. Main housing 102 may be a housing of any suitable shape and made of any suitable material for enclosing any equipment, such as, for example, sensors, motors, and other mechanical, electric, and electronic components. Upper cable head 104 and lower cable head 106 may enclose the tool 100 on the top and bottom ends, respectively, and may be made of a similar material to the main housing 102 or any appropriate material. Anchoring arm 108 allows tool 100, after being lowered into a well, to anchor itself against the wall of the well or casing. Coupling a seismic tool to the well or casing is necessary for quality seismic measurements.
Anchoring arm 108 may be attached to main housing 102 in any suitable manner to allow anchoring arm 108 to switch between closed and open positions. Logging cable 110 may connect tool 100 to other devices, such as, for example, other seismic tools, telemetry devices, or electronic devices that allow tool 100 to transmit data to a computer. For example, tool 100 may be deployed in a string of similar tools, and may be connected to other seismic tools 100 above and below through logging cable 110. Logging cable 110 may be made of any suitable material for supporting the weight of the tools 100 as they are lowered into a well, and may also include cabling for data and power transmission. Tool 100 may receive power and control commands through the logging cable 110.
FIG. 3 depicts an exemplary diagram of an internal view of a tool 100 with a motor. To use anchoring arm 108, tool 100 may include a motor 120 within main housing 102. Motor 120 may be any suitable motor for use within tool 100, such as, for example, an electric motor. Motor 120 may be able to move anchoring arm 108 between closed and open positions, and may be controlled by commands received through logging cable 110. In most traditional down-hole tools, the motor is directly coupled to the anchoring arm. Thus, in case of power failure, it becomes difficult to operate the anchoring arm.
Therefore, a disadvantage of the existing down-hole tools is the lack of anchoring arm's control after the tool is being deployed in the well in the event of a power failure. In addition, when deciding to change a biasing force that acts on the anchoring arm, the process of changing the biasing force is time consuming, laborious and dangerous for the maintenance personnel.
Further, because the downhole tools are used in various wells and applications, the requirements for biasing the arm in or out differs from application to application. In one application, as noted above, when the downhole tools chain is lowered into the well and all the arms are opened and pressured onto the casing, it happens sometimes that a failure prevents from activating the arms back in order to recover the equipment. However, in another application, where the tool chain remains for a long period of time inside the well (e.g., time lapse operation), it is desirable to maintain the tool orientation from day to day. Thus, the arms of the modules in the chain must stay open for days if not months. As is known in the art, opening the arms and maintaining them in the opened position requires electrical energy and the system to be on continuously. This is expensive because of the amount of energy required and/or prone to failure because if the power goes off, the chain might collapse inside the well.
Thus, there is a need for an apparatus and method for a down-hole tool that overcomes the above noted limitations of the existing tools.